NASA’s Mars Reconnaissance Orbiter has returned thousands of fascinating images of our neighbouring world, here is a selection some of the most striking and thought-provoking (false colour) images.
Part of the Martian surface that has cracked into a natural maze, Noctis Labyrinthus (the Labyrinth of Night), lies at the west end of the awesome Valles Marinaris, the Solar System’s greatest canyon. This beautiful image shows a tiny part of the Labyrinth, with both rock layers exposed by erosion and dune fields of sand. Observations of this area have found indications of both iron-based minerals and clay, suggestive of a much wetter past for this region. Resembling the end of rift valleys on our world, the Labyrinth itself was created by similar tectonic forces in the distant past. Sister planets now grown apart, Earth and Mars were once very alike.
Between 3.8 and 3.5 billion years ago the inner planets and our Moon endured a ferocious rain of asteroids which left scars still visible today. Astronomers call this ordeal the Late Heavy Bombardment, and the subject of this striking image, Gale crater, is a relic of these ancient cataclysms. This crater, situated on the edge of Elysium Planitia, is about 150 km across. It is of great interest to students of the history of Mars as it has massive mound of material at its centre. This appears to have been laid down by water. Once there may have been a lake here. NASA considered landing one of its Mars Exploration Rovers in this crater, but ultimately decided against it. The image shows part of the crater’s rim. Gale crater is named for Australian amateur astronomer Walter Frederick Gale.
Once, the goddess Isis was Queen of Heaven to the people of ancient Egypt. Today she is on Mars. A smooth plain of rusty sand and rock was named Isidis Planitia in her honour. Such a featureless landscape is tempting to space mission planners as it ought to be easy to land there. The UK’s Beagle 2 was to have descended here in December 2003 to photograph and poke the Martian soil in search of evidence of life. Alas this was not to be, and now Beagle’s wreckage lies scattered somewhere in these red sands. This area is noticeably almost empty of craters, so the subject of this fascinating image lies just a little south of the Isis’ Plain. So far unnamed, this is a relatively young crater, as evidence just look at those tumbled boulders on its inner slope.
Lying in the Martian tropics, the great plain of Meridiani Planum (Prime Meridian Plain) is currently home to NASA’s Mars Exploration Rover Opportunity which has steadily roamed there since 2004. Observations from both Opportunity and the MRO show that the plain was once covered in water. The whole area is rich in hematite, a mineral formed in water. Once, four billion or so years ago, this may have been the bed of a great lake of iron-rich water. This fossilized landscape was covered by a layer of sediment , only in the past ten million years have the gentle Martian winds scoured this away, revealing to the eyes of Earthlings.This image shows the jagged rim of an unnamed crater lying on the smooth plain.
If you were to trek northwards across the Meridiani Planum, the landscape would make a transition from flat fields of dunes of basalt and hematite sand to a dramatic vista of mesas and plateaus. Here the rocks have been sculpted into dramatic shapes by erosion over the aeons. It may be a long time before any traveler from Earth makes this journey, but this wonderful image will give you a flavour of what to expect.
There was a time when Mars had rivers of fire. Driven by the planet’s internal heat, molten lava burst through great fissures in the planet’s surface, splitting the existing plains and low hills. This possibly even led to cataclysmic floods as subsurface ice was transformed to gushing water. Those days are gone and the Red Planet is in a quieter phase, but geologists can still see the evidence for this past violence. One such piece of evidence is the landscape we can see part of in this fascinating image. This is part of the Cerberus Fossae, deep ravines, where dusty plains suddenly drop down crumbling cliffs of darker grayish stone. This area was named after the three-headed hound which guarded the Greek Underworld by Giovanni Schiaparelli, who also discovered the “canals” of Mars.
Mars has seasons just like our planet, but thanks to its distance the sun, Mars experiences horrifically cold winters. So cold, in fact the very air freezes. Frozen carbon dioxide lies scattered over the majestic sand dunes, only to evaporate in the spring. Sand and dust loosened by this rolls down the sides of the dunes, exposing the darker underlying material. This was happening as this image was made, if you look carefully you can find a plume of dust raised by one of these sudden avalanches.
The numerous dark blobs scattered across the landscape are sites where underground carbon dioxide has erupted as geysers, carrying darker material to the surface. Mars is an earthlike planet, but it is still a very alien world.